Ohm's Law
An empirical relation stating that the electric current flowing through an ohmic conductor is directly proportional to the applied voltage and inversely proportional to resistance.
Governing formula
V = I R, J = σ E
SI unit
V = A · Ω
In depth
Ohmic materials possess a constant electrical resistance R that remains independent of applied voltage or current across normal operating temperatures. Microscopically, current density J is directly proportional to electric field strength E.
Examples in the real world
A 12 V automotive battery driving a 2 A current through a 6 Ω headlight filament.